Where are the extrude and scale values?
There isn't explicit construction history in Blender per se.  If you ever want to know the dimensions of your object for 3d printing, you can always go to the display properties in the viewport, and scroll down until you see the Edge Info buttons under Mesh Display.  Note that you must have fully applied the extrusion operator to see these dimensions.


Move your cursor into the 3d viewport
Press "N" to bring up the Display Properties.
Scroll down the Display Properties until you see Mesh Display
Check off whichever buttons (Edge length, angle, or Face area) applies to what you're interested in.
Select the face/edges that you want to know the dimensions of.